"Lazy" far-lateral approach to the anterior foramen magnum and lower clivus.

ABSTRACT

The far-lateral approach (FLA) has become a mainstay for skull base surgeries involving the anterior foramen magnum and lower clivus. The authors present a surgical technique using the FLA for the management of lesions of the anterior/ anterolateral foramen magnum and lower clivus. The authors consider this modification a "lazy" FLA. The vertebral artery (VA) is both a critical anatomical structure and a barrier that limits access to this region. The most important nuance of this FLA technique is the management of this critical vessel. When the lazy FLA is used, the VA is reflected laterally, encased in its periosteal sheath and wrapped in the dura, greatly minimizing the risk for vertebral injury while preserving a wide working space. To accomplish this step, drilling is performed lateral to the point where the VA pierces the dura. The dura is incised medial to the VA entry point by using a slightly curved longitudinal cut. Drilling of the condyle and the C-1 lateral mass is performed in a manner that preserves craniocervical stability. The lazy FLA is a true FLA that is based on manipulation of the VA and lateral bone removal to obtain excellent exposure ventral to the spinal cord and medulla, yet it is among the most conservative FLA techniques for management of the VA and provides a safer window for bone work and lesion management. Among 44 patients for whom this technique was used to resect 42 neoplasms and clip 2 posterior inferior cerebral artery aneurysms, there was no surgical mortality and no injury to the VA.